xeljanz can lower your ability to fight infections, including tuberculosis. serious, sometimes fatal infections and cancers have happened in patients taking xeljanz. don't start taking xeljanz if you have any kind of infection, unless ok with your doctor. tears in the stomach or intestines, low blood cell counts and higher liver tests and cholesterol levels have happened. your doctor should perform blood tests, including certain liver tests before you start, and while you are taking xeljanz. tell your doctor if you have been to a region where certain fungal infections are common, and if you have had tb, hepatitis b or c, or are prone to infections. tell your doctor about all the medicines you take, and if you are pregnant, or plan to be. taken twice daily, xeljanz can reduce the joint pain and swelling of moderate to severe ra, even without methotrexate. ask if xeljanz is right for you.